Model systems will be used to characterize the protection that glutathione peroxidase affords sensitive isocitrate dehydrogenase from damage by hydroperoxides. Isolation, purification, and identification of fluorescent products of lipid peroxidation in microsomes, animal tissues, and model systems will be undertaken. HPLC, TLC and GC techniques will be used. The fluorescent products of the structural proteins elastin and collagen will be identified and the significance of their increase during aging and atherosclerosis will be determined. Gas chromatographic techniques will be used to measure in concentrated breath samples the lipid peroxidation products ethane and pentane during the feeding of various levels of vitamin E to rats and during and after various imposed oxidant stresses. BIBLIOGRAPHIC REFERENCES: Trombly, R., A.L. Tappel, J.G. Coniglio, W.M. Grogan, Jr. and R.K. Rhamy. Fluorescent products and polyunsaturated fatty acids of human testes. Lipids 10:591-596 (1975). Tappel, A.L. Lipid peroxidation and fluorescent molecular damage to cell membranes. In: "Pathobiology of Cell Mebranes," Vol. 1, B.F. Trump and A.U. Arstila, eds. Academic Press, New York, N.Y., pp. 145-170, 1975.